Method of System Information Transmission and Acquisition

ABSTRACT

A method of system information transmission for a network in a wireless communication system is disclosed. The method comprises broadcasting essential minimum system information (SI) of a cell of the wireless communication system with fixed scheduled on a downlink broadcast channel, wherein the essential minimum SI includes scheduling information for non-essential minimum SI of at least one of the cell and an auxiliary cell or a frequency location, the non-essential minimum SI is broadcasted with dynamically scheduled on a downlink shared channel, and the scheduling information includes a time and frequency resource configuration and an availability information for indicating whether the cell broadcasts the non-essential minimum SI.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/453,527, filed on Feb. 2, 2017 and entitled “Design of New RadioAccess Technology System Information”, the contents of which areincorporated herein in their entirety.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a method used in a wirelesscommunication system, and more particularly, to a method of systeminformation transmission and acquisition in the wireless communicationsystem.

2. Description of the Prior Art

3GPP in 5G new radio (NR) access technology proposes standalone andnon-standalone NR cell deployment. Standalone cell can be selected andaccessed by a UE without assistance information from other cells,whereas non-standalone cell cannot be selected nor accessed by a UEwithout assistance information from other cells.

In addition, system information (SI) of 5G NR system includes essentialminimum system information, which is fixed scheduled on a physicaldownlink broadcast channel (e.g., the physical broadcast channel (PBCH)of LTE or the NR-PBCH of 5G NR) and is organized into single systeminformation block (SIB), non-essential minimum SI, which is dynamicallyscheduled on a physical downlink shared channel (e.g., the physicaldownlink share channel (PDSCH) of LTE or the NR-PDSCH of 5G NR) and isorganized into one or more system information blocks (SIBs), and otherSI, which could be periodically broadcast or on-demand, namely requestedby the UE.

Fixed scheduled implies the size of the data unit is fixed, the volumeof the radio resource to transmit the data unit is fixed, the radioresource location for transmitting the data unit is fixed in frequencydomain, and the periodicity is fixed in time domain. Dynamicallyscheduled implies the size of the data unit could be dynamic, the volumeof the radio resource to transmit the data unit could be dynamicallyarranged by the network, the radio resource location for transmittingthe data unit is dynamically arranged by the network side in frequencydomain, the periodicity of the present of the radio resource fortransmitting the data unit is dynamically arranged by the network intime domain.

Based on the current mechanism, not every NR cell broadcasts SI or theentire SI, and there may be cells in the system on which the UE cannotcamp and do not broadcast the entire SI, such as non-standalone cells.However, there is no specification for a UE to determine whether a cellis campable or not, which causes power consumption and time delay incell selection. Besides, there is no specification for the UE to know SIor SIB is periodically broadcasted or on-demand, and thus the UE may notknow how to acquire the SI/SIB.

SUMMARY OF THE INVENTION

It is therefore an objective to provide a method of system informationtransmission and acquisition to solve the above problem.

The present invention discloses a method of system informationtransmission for a cell in a wireless communication system. The methodcomprises broadcasting essential minimum system information of the cellof the wireless communication system with fixed scheduled on a downlinkbroadcast channel, wherein the essential minimum SI includes schedulinginformation for non-essential minimum SI of at least one of the cell andan auxiliary cell or a frequency location, the non-essential minimum SIis broadcasted with dynamically scheduled on a downlink shared channel,and the scheduling information includes a time and frequency resourceconfiguration and an availability information for indicating whether thecell broadcasts the non-essential minimum SI.

The present invention discloses a method of system informationacquisition for a mobile device in a wireless communication system. Themethod comprises receiving essential minimum system information of acell of the wireless communication system with fixed scheduled on adownlink broadcast channel, wherein the essential minimum SI includes afirst scheduling information for non-essential minimum SI, and the firstscheduling information includes a time and frequency resourceconfiguration and an availability information for indicating whether thecell broadcasts the non-essential minimum SI, and determining whetherthe cell is campable according to the availability information of thefirst scheduling information.

These and other objectives of the present invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an exemplary communication device.

FIG. 2 is a flowchart of an exemplary process according to the presentdisclosure.

FIGS. 3-7 are schematic diagrams of system information schedulingaccording to the present disclosure.

FIG. 8 is a flowchart of an exemplary process according to the presentdisclosure.

FIGS. 9-12 are schematic diagrams of system information acquisitionaccording to the present disclosure.

DETAILED DESCRIPTION

FIG. 1 is a schematic diagram of an exemplary communication device 10.The communication device 10 can be a user equipment (UE) or a cellularbase station. The communication device 10 may include a processing means100 such as a microprocessor or Application Specific Integrated Circuit(ASIC), a storage unit 110 and a communication interfacing unit 120. Thestorage unit 110 may be any data storage device that can store programcode 114 and stored data 115, for access by the processing means 100.Examples of the storage unit 110 include but are not limited to asubscriber identity module (SIM), read-only memory (ROM), flash memory,random-access memory (RAM), CD-ROMs, magnetic tape, hard disk, andoptical data storage device. The communication interfacing unit 120 ispreferably a radio transceiver and can exchange wireless signalsaccording to processing results of the processing means 100.

Please refer to FIG. 2, which is a flowchart of a process 20 accordingto an example of the present disclosure. The process 20 is utilized inthe base station of FIG. 1, hereafter referred to a cell (e.g. a macrocell, micro cell, small cell, etc.), for SI transmission. The systeminformation (SI) may be stored in the storage unit 110. The process 20may be compiled into a program code 114 to be stored in the storage unit110, and may include the following steps:

Step 200: Start.

Step 210: Broadcast essential minimum SI with fixed scheduled on adownlink broadcast channel, wherein the essential minimum SI includesscheduling information for non-essential minimum SI of at least one ofthe cell and an auxiliary cell, and the non-essential minimum SI isbroadcasted with dynamically scheduled on a downlink shared channel,wherein the cell includes a time and frequency resource configuration ofthe non-essential minimum SI in the scheduling information if the cellbroadcasts the non-essential minimum SI, whereas the cell includesavailability information for indicating that the cell does not broadcastthe non-essential minimum SI in the scheduling information if the celldoes not broadcast the non-essential minimum SI.

Step 220: End.

According to the process 20, the cell transmits the schedulinginformation of the essential minimum SI with parameter to indicatewhether the cell is campable. In detail, the cell includes theavailability information in the essential minimum SI to assist cellselection in 5G NR system.

In detail, the essential minimum SI includes scheduling information forthe non-essential minimum SI and an identity of the essential minimumSI. Therefore, a UE could store the essential minimum SI with theidentity, and may not re-acquire the stored essential minimum SI. In anexample, the identity of the essential minimum SI includes a timingindex. The scheduling information of the essential minimum SI includes atype identifier to identify the type of the non-essential minimum SIassociated with the essential minimum SI, which includes the associationof the numerology for the non-essential minimum SI, availabilityinformation (e.g. Enumerate {true, false}) to identify whether the cellbroadcasts any non-essential minimum SI, frequency location forassociating the non-essential minimum SI with the essential minimum SI,bandwidth, and timing information for associating the non-essentialminimum SI with the essential minimum SI.

Please refer to FIG. 3, which illustrates an embodiment of SIscheduling. The UE detects a frequency location and bandwidth to selecta cell, and then receives the essential minimum SI of the selected cellon the fixed scheduled broadcast channel that the size and periodicityof the information carried by which is predefined in the specificationdepending on carrier frequency range. The essential minimum SI isusually a single system information block (SIB), such as masterinformation block (MIB), and includes at least one of schedulinginformation 300 a for non-essential minimum SI of the selected cell andscheduling information 300 b for non-essential minimum SI of theauxiliary cell or frequency location. The non-essential minimum SI isusually one or more SIBs transmitted by one or more SI messages ondynamic scheduled downlink shared channel. In an example, thenon-essential minimum SI could be a system information block type 1(SIB1) and could be transmitted via a radio resource control (RRC)message from the network. In addition, the scheduling information 300 aor 300 b include information of associated SIB 1 CORESET (ControlResource Set, which indicates the radio resource configuration of SIB1including at least the configuration information of frequency, time,bandwidth, common search space). Thus, the UE receives the non-essentialminimum SI on the DL shared channel that the size and periodicity of theinformation carried by which is dynamically scheduled depending oncarrier frequency range and/or time according to the schedulinginformation 300 a or 300 b of the essential minimum SI. Note that, theavailability information of the scheduling information 300 a or 300 b inthe essential minimum SI are used for quickly identifying whether thenon-essential minimums SI is presented in or broadcasted by the selectedcell, so as to determine whether the selected cell is campable. In anexample, the availability information is included in a 8-bit ofinformation of the SIB1 CORESET.

In addition, the content of the received non-essential minimum SIincludes supported bandwidth (e.g. in terms of resource blocks (RBs)),validity information, a list of public land mobile network identity(PLMN ID), a cell ID, at least one of scheduling information 302 a and302 b for the remaining parts of the non-essential minimum SI (multipleSIBs) and other SI (may include multiple SIBs of selected cell and mayinclude multiple SIBs of auxiliary cells), number of downlink and/oruplink beam sweeps, and downlink and/or uplink beam configuration. Thescheduling information 302 a and 302 b may include SI mappinginformation for associating at least a system information block (SIB)with a message for SI transmission, repetition information, SI windowlength, and an availability indication for indicating that the SIB isperiodically broadcasted or on-demand. Thus, the UE receives theremaining parts of the non-essential minimum SI with dynamic scheduledon the DL shared channel according to the scheduling information 302 aor 302 b of the non-essential minimum SI. The validity informationincludes an identity of the non-essential minimum SI, versioninformation (e.g. a value tag, version number), wherein the versioninformation of the non-essential minimum SI changes if the content ofone or more information blocks of non-essential minimum SI change, andan applicable area ID (e.g. one or more area codes/group codes/physicalcell IDs). In an embodiment, the identity of the non-essential minimumSI includes time domain positions of the transmitted synchronizationsignal blocks (SS-blocks) in an SS-Burst-Set as defined in 3GPP TS38.213.

Moreover, the content of the remaining parts of the non-essentialminimum SI includes the following information:

1. A list of information to present the availability of SIBs/SI messagesprovided by the selected cell and auxiliary cell/frequency. Each entityof the list may include:

1-1. An identity of the SIB/SI message: the identity of the SIB/SImessage that is provided by the selected cell and auxiliarycell/frequency;

1-2. Availability indication: SIB/SI message is periodically broadcastedor on-demand (i.e. the SIB/SI message is transmitted based on UEacquisition; the system information is transmitted by the network uponreceiving at least a request from one or more UEs for acquiring the SIBor the SI message); and

1-3. Version info: e.g., version number or value tag, wherein theversion info is per-SIB specific;

2. A list of scheduling information 304 a-304 b for other SI (i.e. oneor multiple SIBs/SI messages) related to other cells or other RATs, eachentity of the list may include:

2-1. SI mapping info;

2-2. Repetition info; and

2-3. SI window length.

Note that, based on the availability indication of the remaining partsof the non-essential minimum SI, the UE knows the SIBs/SI messages isperiodically broadcasted or on-demand, so as to acquire the SIBs/SImessages. In addition, the scheduling information 304 a-304 b associatedwith on-demand SIB/SI message may be pre-scheduled regardless of theactual being broadcast or not of the on-demand SIB/SI message at theinstant in time, or the scheduling information 304 a-304 b associatedwith on-demand SIB/SI message may be scheduled dynamically regarding thebroadcast of the on-demand SIB/SI message.

For more system information scheduling example, reference is made toFIGS. 4-7. In FIG. 4, the content of the essential minimum SI ofselected cell includes the scheduling information 400 only for thenon-essential minimum SI of the selected cell, and the non-essentialminimum SI of the selected cell may include the scheduling information402 a for the non-essential minimum SI of auxiliary cell or frequencylocation, remaining parts of non-essential minimum SI of the selectedcell, and other SI of other cells or other RATs. On the other hand, thenon-essential minimum SI of auxiliary cell or frequency locationincludes scheduling information 402 b for the remaining parts ofnon-essential minimum SI and other SI of other cells or other RATs.

Compared to the abovementioned embodiment of FIG. 4, the non-essentialminimum SI of auxiliary cell or frequency location of FIG. 5 includesthe scheduling information 502 b only for the remaining parts ofnon-essential minimum SI of auxiliary cell or frequency location, andthe remaining parts of non-essential minimum SI of auxiliary cell orfrequency location includes the scheduling information 504 b for theother SI of other cells or other RATs.

In FIG. 6, the non-essential minimum SI of the selected cell does notinclude the scheduling information for the non-essential minimum SI ofauxiliary cell or frequency location, whereas the scheduling informationfor the non-essential minimum SI of auxiliary cell or frequency locationis includes in the other SI of other cells or other RATs.

Compared to the abovementioned embodiment of FIG. 4, in FIG. 7, theessential minimum SI of selected cell includes the schedulinginformation 700 only for the non-essential minimum SI of auxiliary cellor frequency location. The non-essential minimum SI of auxiliary cell orfrequency location includes the scheduling information 702 b for theremaining parts of non-essential minimum SI and other SI of auxiliarycell or frequency location.

Please refer to FIG. 8, which is a flowchart of a process 80 accordingto an example of the present disclosure. The process 80 is utilized inthe UE of FIG. 1 for SI acquisition. The process 80 may be compiled intoa program code 114 to be stored in the storage unit 110, wherein theinformation received during process 80 may be stored into the storeddata 115 of the storage unit 110 and may include the following steps:

Step 800: Start.

Step 810: Receive essential minimum system information (SI) of a cell ofthe wireless communication system with fixed scheduled on a downlinkphysical broadcast channel, wherein the essential minimum SI includesscheduling information for non-essential minimum SI, and the schedulinginformation includes a time and frequency resource configuration of thenon-essential minimum SI if the cell broadcasts the non-essentialminimum SI, whereas the scheduling information includes availabilityinformation indicating the cell does not broadcast the non-essentialminimum SI if the cell does not broadcast the non-essential minimum SI.

Step 820: Determine whether the cell is campable according to theavailability information of the scheduling information included in theessential minimum SI.

Step 830: End.

According to the process 80, the UE determines whether the cell iscampable or barred, and knows how to acquire the non-essential minimumSI according to the parameters included in the scheduling information ofthe received essential minimum SI. For example, the UE knows that thecell is campable if the availability information indicates that theselected cell broadcasts the non-essential minimum SI for cell selectionand cell access.

Please refer to FIG. 9, which illustrates system information acquisitionfor cell selection according to the present disclosure. First, the UEreceives the essential minimum SI from the selected cell, and determineswhether the selected cell broadcasts the non-essential minimum SI of theselected cell or broadcasts the non-essential minimum SI of theauxiliary cell/frequency location according to the availabilityinformation indicating the presence or absence of the non-essentialminimum SI. If the selected cell does not broadcast the non-essentialminimum SI, the UE determines that the selected cell is not campable orbarred. When UE detects the selected cell does not broadcast thenon-essential minimum SI, the UE may further check whether a validnon-essential minimum SI of the selected SI is stored in the UE beforedetermining that the selected cell is not campable or barred; if a validnon-essential minimum SI of the selected SI is stored in the UE, the UEmay utilize the stored non-essential minimum SI (steps 900 and 902). Thevalidity of the stored non-essential minimum SI could be determined bye.g., a timer. On the other hand, if the selected cell broadcasts thenon-essential minimum SI, the UE receives the non-essential minimum SIwith the abovementioned scheduling information of FIGS. 3-7 (step 906).If the select cell broadcasts neither the non-essential minimum SI ofthe selected cell nor the auxiliary cell or frequency location, andthere is no valid non-essential minimum SI associated with the selectedcell stored in the UE, the UE determines that the selected cell isnon-campable (step 904). On the other hand, if the selected cellbroadcasts neither the non-essential minimum SI of the selected cell northe auxiliary cell or frequency location, but there is validnon-essential minimum SI associated with the selected cell stored in theUE, the UE receives the non-essential minimum SI and determines whetherthe entire minimum SI (i.e., the essential minimum SI and the entirenon-essential minimum SI) is obtained (step 908). If yes, the UEprovides the information received from the essential minimum SI to thenon-access stratum (NAS) layer for cell selection or reselection (step90X). The UE may select and camp on the cell based on NAS decision andthe RRC criteria for selecting a cell are fulfilled (steps 90Y and 910).If the entire minimum SI does not be obtained, the UE determines theselected cell is non-campable (step 904). In addition, the UE may obtainthe remaining part of the non-essential minimum SI and/or the other SIif the non-essential minimum SI includes scheduling information of theremaining part of the minimum SI and/or the other SI, the UE receivesthe remaining part of non-essential minimum SI and/or other SIaccordingly.

Compared to the embodiment of FIG. 9, if the select cell does notbroadcast the non-essential minimum SI of the selected cell, the UEdetermines that the selected cell is non-campable or barred, as shown inFIG. 10.

Moreover, reference is made to FIG. 11 for SI acquisition. The UEobtains the scheduling information of the remaining parts of thenon-essential minimum SI of a cell included in the non-essential minimumSI of the selected cell (step 1100), and then determines whether theSIBs interested by the UE is provided by the cell (e.g., determined bywhether the interested SIB is presented in the scheduling information)(step 1102). If the interested SIB is not provided by the selected cell,the UE may de-prioritize the cell, and may select other cells (step1104). If the interested SIB is provided by the selected cell, the UEmay further determining (e.g., by comparing the validity information ofthe interested SIB in the scheduling information and the validityinformation of the interested SIB stored in the UE) whether to obtainthe interested SIB from the serving cell or to utilize the informationof the interested SIB stored by the UE. If the interested SIBs areprovided by the cell and the UE decides to obtain the interested SIBfrom the serving cell, the UE further checks whether the interested SIBsare broadcasted periodically according to availability indication of theremaining parts of non-essential minimum SI (step 1106). If yes, the UEobtains the interested SIBs according to the scheduling information ofthe remaining parts of non-essential minimum SI of the cell (steps1108). Note that, in an embodiment, the scheduling information may beobtained from other cell on the same or different frequencies or fromstored SI. If the interested SIB is on-demand, the UE sends one or moreSI request signals to the cell to acquire the interested SIB withoutwaiting for the SI window of the interested SIB (i.e., UE sends SIrequest immediately) (step 1114), and then receives the interested SIBsfrom the cell according to the scheduling information of the cell (steps1118).

Compared to the embodiment of FIG. 11, after the UE determines that theinterested SIBs are on-demand, the UE does not immediately send the SIrequest, but monitors the SI window of the interested on-demand SIBbefore sending the SI request, as shown in FIG. 12. If the UE receivesthe interested SIBs during the SI window, the UE does not send the SIrequest for SIB acquisition; otherwise, UE sends SI request to acquirethe interested SIB. The SI request could be SIB-specific request or SImessage specific request. The SI request could be a preamble associatedwith the interested SIB or SI message, a MAC control element includesthe ID of the acquired SIB or SI message, or a RRC message indicates theacquired SIB or SI messages.

The abovementioned steps of the processes including suggested steps canbe realized by means that could be a hardware, a firmware known as acombination of a hardware device and computer instructions and data thatreside as read-only software on the hardware device or an electronicsystem. Examples of hardware can include analog, digital and mixedcircuits known as microcircuit, microchip, or silicon chip. Examples ofthe electronic system can include a system on chip (SOC), system inpackage (SiP), a computer on module (COM) and the communication device10.

In conclusion, the present invention addresses to contents/parameters ofsystem information for cell selection, cell access and SI acquisition.In detail, the cell includes the availability information in thescheduling information. Thus, the UE knows whether the cell is campableand how to acquire the non-essential minimum SI according to thereceived SI.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the invention. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

What is claimed is:
 1. A method of system information transmission for acell in a wireless communication system, the method comprising:broadcasting essential minimum system information (SI) of the cell ofthe wireless communication system with fixed scheduled on a downlinkbroadcast channel; wherein the essential minimum SI includes a firstscheduling information for non-essential minimum SI of at least one ofthe cell and an auxiliary cell or a frequency location, thenon-essential minimum SI is broadcasted with dynamically scheduled on adownlink shared channel, and the scheduling information includes a timeand frequency resource configuration and an availability information forindicating whether the cell broadcasts the non-essential minimum SI. 2.The method of claim 1, wherein the essential minimum SI further includesan identity of the essential minimum SI, and the first schedulinginformation further includes a type identifier for the non-essentialminimum SI, bandwidth, carrier frequency information for associating thenon-essential minimum SI with the essential minimum SI, and timinginformation for associating the non-essential minimum SI with theessential minimum SI.
 3. The method of claim 1, wherein thenon-essential minimum SI includes at least one of a supported bandwidth,a validity information, an identity of the non-essential minimum SI, aversion information, an applicable area identity, a second schedulinginformation for at least one of remaining parts of the non-essentialminimum SI and other SI related to other cells or other radio accesstechnologies (RATS), a list of public land mobile network (PLMN)identities, a cell identity, number of downlink beam sweeps, anddownlink and uplink beam configuration.
 4. The method of claim 3,wherein the remaining parts of the non-essential minimum SI includes athird scheduling information for the other SI.
 5. The method of claim 1,wherein the non-essential minimum SI of the selected cell includes thescheduling information for the non-essential minimum SI of the auxiliarycell or the frequency location.
 6. The method of claim 3, wherein theother SI includes scheduling information for the non-essential minimumSI of the auxiliary cell or the frequency location.
 7. The method ofclaim 3, wherein the second scheduling information includes at least oneof SI mapping information for associating at least a system informationblock (SIB) with a message for SI transmission, repetition information,SI window length and an availability indication for indicating that theSIB is periodically broadcasted or on-demand.
 8. The method of claim 3,wherein the applicable area identity includes at least one of areacodes, group codes, physical cell identities.
 9. The method of claim 7,wherein the transmission resource of the on-demand SIB is pre-scheduled.10. A method of system information acquisition for a mobile device in awireless communication system, the method comprising: receivingessential minimum system information (SI) of a cell of the wirelesscommunication system with fixed scheduled on a downlink broadcastchannel, wherein the essential minimum SI includes a first schedulinginformation for non-essential minimum SI, and the first schedulinginformation includes a time and frequency resource configuration and anavailability information for indicating whether the cell broadcasts thenon-essential minimum SI; and determining whether the cell is campableaccording to the availability information of the first schedulinginformation.
 11. The method of claim 10, further comprising: obtainingthe non-essential minimum SI with dynamic scheduled on a downlink sharedchannel according to the first scheduling information of the essentialminimum SI when the availability information indicates that the cellbroadcasts the non-essential minimum SI; determining whether the cellbroadcasts the remaining parts of the non-essential minimum SI accordingto a second scheduling information included in the obtainednon-essential minimum SI; and obtaining the remaining parts of thenon-essential minimum SI according to the second scheduling information.12. The method of claim 11, further comprising selecting the cell foraccess when the essential minimum SI and the non-essential minimum SIare obtained.
 13. The method of claim 10, wherein determining whetherthe cell is campable according to the availability information of thefirst scheduling information comprises: checking if the non-essentialminimum SI is stored in the mobile device or is valid when theavailability information indicates that the cell dose not broadcast thenon-essential minimum SI; determining that the cell is not campable whenthe first availability information indicates that the cell does notbroadcast the non-essential minimum SI and the non-essential minimum SIis not stored in the mobile device or is not valid.
 14. The method ofclaim 11, further comprising: determining whether the cell broadcaststhe remaining parts of the non-essential SI for an auxiliary cell or afrequency location according to the second scheduling informationincluded in the non-essential minimum SI; and obtaining the remainingparts of the non-minimum SI for the auxiliary cell or the frequencylocation according to the first scheduling information when the cellbroadcasts the remaining parts of the non-essential minimum SI for theauxiliary cell or the frequency location.
 15. The method of claim 11,further comprising: determining whether the cell provides a systeminformation block (SIB) interested by the mobile device according to thesecond scheduling information of the obtained non-essential minimum SI;and determining whether the interested SIB is broadcasted periodicallyor transmitted on-demand according to the second scheduling information.16. The method of claim 15, further comprising: monitoring a SI windowfor the interested SIB according to the second scheduling information toobtain the interested SIB before sending the SI request when determiningthe interested SIB is on-demand; determining whether the interested SIBis obtained during the scheduled SI window according to the secondscheduling information; sending a SI request to request the interestedSIB to the cell when determining the interested SIB is provided by thecell and is on-demand but the interested SIB is not obtained during thescheduled SI window.
 17. The method of claim 15, further comprising:deprioritizing the cell when the cell does not broadcast the interestedSIB.
 18. The method of claim 15, further comprising: obtaining theinterested SIB according to the second scheduling information whendetermining the interested SIB is periodically broadcast; sending a SIrequest to request the interested SIB to the cell when determining theinterested SIB is on-demand; and obtaining the interested SIB accordingto the second scheduling information after sending the SI request.